1. Field
One or more embodiments relate to an electrode assembly and a lithium rechargeable battery comprising the same.
2. Description of the Related Technology
Lithium rechargeable batteries include an electrode assembly that includes a positive electrode, a negative electrode and a separator, as well as an electrolyte and a case for accommodating the electrode assembly and the electrolyte.
The positive electrode is formed by coating a positive electrode active material on a positive electrode current collector. Examples of the positive electrode active material may include lithium cobalt oxide, lithium manganese oxide and lithium nickel oxide. Specifically, a lithium manganese oxide (LMO)-based active material is widely used in view of its cost effectiveness. However, the manganese (Mn) contained in the positive electrode active material may be eluted during charging/discharging of battery, resulting in a gradual reduction in the battery's capacity with repeated charging/discharging cycles. Also, the battery capacity may be rapidly reduced when the battery is stored at high temperature for an extended period.
To overcome this problem, a type of conventional rechargeable battery has been manufactured using a mixture of other positive electrode active materials with varying composition ratios. However, this mixtures of other positive electrode active materials is more expensive than the lithium manganese oxide (LMO)-based active material. Thus, as the composition ratio increases, the battery performance may become better. However, increasing the composition ratio may adversely affect the cost.